New, Greener Flame Retardant Targets Styrenics

Albemarle Corp, a leading flame retardant producer for engineering plastics, has developed an environmentally friendly replacement for decabromodiphenyl ether, which has been banned for use in electrical and electronic enclosures in Europe and in two states.

The development is significant because decabrom has long been a workhorse flame retardant that allowed safe use of many important plastics, particularly the styrenics. Despite protests from suppliers, the use of decabrom has been curtailed because of various health and environmental concerns.

The new material, called Earthwise GreenArmor, is expected to be commercially available in the second half of 2010.

"Based on the testing we've done it can be used in as many applications as decarbrom has been," says Dave Clary, chief sustainability officer for Albemarle. He says the new material has properties that are at least equal to, and sometimes better than decabrom. Two areas of improvement noted in the test are improved surface appearance of parts made with the additive, and a higher melt flow rate. The new materials are also melt blendable.

Albemarle describes GreenArmor as "organic" because it is produced with a proprietary polymeric backbone. Bromine is incorporated into the compound to provide flame retardance. "There are some resins that cannot be flame retarded without a halogen," says Clary. Bromine is a member of the halogen family. Some difficult-to-flame-retard resins include ABS and high-impact polystyrene.

Polymeric compounds are considered safer under European Union REACH guidelines than mineral compounds. It's also significant that there is much less bromine in GreenArmor than some plastic compounds, which can be loaded as high as 50 percent with decabrom to achieve flame retardance.

"It's important that it's a polymeric material because that means it's not absorbable into the body," says Clary.

GreenAmror is the first product in a broad-based program at Albemarle to develop specialty chemical products that are environmentally friendly. A wide variety of chemistries probably will be used, says Clary. Some of the criteria for the program are said to include improved recyclability or reuse, use of non toxic, non-bioaccumulative materials and a favorable greenhouse gas footprint.

Compounds containing GreenArmor can be easily recycled, says Clary. That isn't necessarily the case with plastic compounds that are flame retarded using other technologies. In some cases, the flame retardant could sufficiently weaken mechanical proprieties of the plastics to prohibit re-use.

Pricing for the new material has not yet been established. Clary says Albemarle has tested GreenArmor in ABS, high-impact polystyrene, nylons, and other plastics.

Meanwhile, Albemarle strongly defends bromine chemistry.

"Bromine has gotten kind of a bad rap," says Clary. "There is a wide variety of brominated flame retardants and brominated products in general. And they all have different properties and they tend to get grouped into one category because there have been a couple of products where there has been concern or proof of harm. Most of them are no longer on the market. The good side of bromine is that is very effective at flame retarding difficult plastics, so it allows us to have safe products.